There's no such thing as fiction that's propaganda against a fictional race/people; that's just plain fiction (even if it has potentially unsavory overtones).
Propaganda that's part of a story is still propaganda.
Y'know what? Back in the 1970s and '80s, SF author F.M. Busby wrote a series of novels about the Hulzein family, in a dystopian near-future setting that had government by corporations that began in the U.S. (because the current form of government was financially unsustainable, and overrun by climate refugees from other parts of the world).
One of them annexed Canada and Mexico (sounds familiar on the nightly news now, since Trump won't shut up about it). The next one that took over decided to take over the entire planet, by whatever means it had to. The only holdouts were Argentina and Australia, both controlled by different factions of the Hulzeins (very wealthy in money and resources and had the means to keep the corporations out).
I met Busby at a convention in the late 1980s and mentioned seeing things on the news that suggested that some things in his books could come to pass (government by corporation, for instance), and there were already rumblings about Total Welfare - locking up the homeless, the low-income who couldn't pay their bills and forcing them to work off their debt - but the system was structured so hardly any of them ever managed it. Total Welfare eventually became a dumping ground for political prisoners, as well.
Busby disagreed with me, saying, "They're only stories." He died before a lot of the real crap in the 2000s started, and I've sometimes wondered what he would make of today's world. It's right out of a number of SF works I can think of, like The Handmaid's Tale. Atwood wrote that as a warning, but there's a faction in the U.S. that seems to take it as a how-to manual for oppressing minorities and women. They're already stopping people who are going to Canada and searching their vehicles, asking more pointed questions - and those are on the American side, not the Canadian border agents.
How long before pregnant women won't be allowed out of the U.S.?
So propaganda is a valid part of a fiction story, whether original or fanfic. The author may intend it for a particular audience of readers, or may hope to get a general audience thinking about some concept in the story. And of course there's the in-universe effect on the characters.
I find one of the hardest things with multiculturalsim is, even more than different priorities, is when one group places a much higher priority on an issue that another group.
As someone who lives in a multicultural country, this is true to a large extent. Someone from a particular background might run for a party you favor, but due to the emphasis they place on certain issues that you might not agree are important, it will affect whether or not you want to vote for this person and will opt for someone else.
This is why I changed my usual voting habit in the recent Canadian federal election. I wasn't wholly convinced that a couple of candidates I might have preferred were completely on board with what is good for the country, so I ignored them and went with another candidate for a party I haven't voted for in years. I was able to vote with a clear conscience.